Heat cleanable coating for glass fibers

ABSTRACT

Glass fibers coated with an easily heat cleanable size comprising a high boiling organic lubricant and a methacrylate polymer or copolymer.

A limited States Patent Inventor Appl. No.

Filed Patented Assignee Homer G. Hill Newark, Ohio Dec. 13, 1967 Aug..17, 1971 Owens-Corning Fiberglas Corporation HEAT CLEANABLE COATING FORGLASS FIBERS 12 Claims, No Drawings GR, 126 GS, 126 GO; 65/3; 57/1.4

References Cited UNITED STATl-IS PATENTS 12/1948 ll/1954 l/1966 8/1969Ebaugh Radke Vanderbilt Marzocchi et a1. Kolek et a1 PrimaryExaminer-William D. Martin Assistant Examiner-David CohenAttorneys-Staelin and Overman and William P. Hickey 117/126X 1l7/126Xl17/126X 117/126X ABSTRACT: Glass fibers coated with an easily heatcleanable size comprising a high boiling o methacrylate polymer orcopolymer.

rganic lubricant and a Glass fibers are produced by several differentmethods. In one method, small molten streams of glass are attenuated bythe pulling action of a winding drum on which they are wound in excessof 10,000 feet per minute. Before reaching the drum and while in a solidstate, the attenuated fibers are brought together into a strand which istraversed back and forth across the winding drum. In another process ofmaking glass fibers, molten streams of glass are attenuated by aconfined downward blast of air which attenuates and projects the fibersonto a perforated collecting drum through which air is continuallyexhausted. The fibers which collect upon the surface of the drum arerandomly oriented, and are discontinuous with the average fiber lengthbeing approximately 1 foot long. The veil of fibers which is collectedon the surface of the drum is withdrawn and pulled axially through asmall cylinder that is revolved by a turbine to collect and twist thediscontinuous fibers into a sliver. The sliver is passed over a windertraverse and wrapped around a tube to produce a wound package of thesliver.

Both the continuous filament strand and the discontinuous filamentsliver have many uses, one of which is in the making of woven fabrics.Fibers made by no matter what process, are extremely susceptible toabrasion and must be protected by an organic film former which bothseparates the fibers and lubricates the surface thereof to preventabrasion by the guide surfaces of the processingequipment. The glassfibers by both processes described above are used to make woven fabrics,the manufacture of which, requires the strand or sliver, as the case maybe, to go through a number of operations including twisting, quilling,beaming and weaving. In order to protect the fibers from abrasion duringthese processing steps, an organic film former is applied to the fibersat forming prior to or during the gathering of the fibers together intothe strand or sliver, as the case may be. In some respects, the abradingac tion of the air turbine used to gather discontinuous filaments into asliver is more severe than the abrading action of the equipment whichproduces the strand. The film former which is applied to the filamentsforming the sliver must be capable of not only forming a film whichprotects the filaments, but must also have lubricating properties toprotect the air turbine.

The lubricating properties that are required to be provided in theprotective coatings are so peculiar that very few materials will providethem, and those materials which provide the lubricity will not provide asurface which can be dyed and will not provide lasting protection. Thecoatings which are applied at forming, therefore, are removed after thefibers are woven into a fabric. This is usually accomplished by aheat-cleaning process in which the woven fabric is passed through anoven having a temperature of above approximately 900 F. to oxidize andremove the coatings. This heat treatment also sets the weave of thefabric, and immediately thereafter a finish,

usually a colored protective coating, is applied.

The problem to which the present invention is directed concerns the burnoff of the protective coating applied at forming. The principal probleminvolved with most protective coatings is that they leave black carbondeposits as a result of the heat treating of the fabric. The protectivecoatings that are applied to the sliver contain an organic lubricantwhich leaves a pronounced carbon residue upon burn off. The presentinvention, therefore, is directed to a film forming material whichcontains an organic lubricant and which will nevertheless have asubstantially complete burn-off during the heat-cleaning operation ofthe fabric.

The principal object of the present invention is the provision of a newand improved protective coating for application bu e le to glassfibersatforming which,will havesubstantially,

f i -prst mstslx210; er entqtthesmmnm Another object of the invention isthe provision of new and improved coated glass fibers, the coating ofwhich can be completely removed during heatcleaning without leaving acarbon deposit.

SUMMARY OF THE INVENTION The invention relates generally to a coatingmaterial for glass fibers which will completely protect the fibersagainst abrasion even when twisted by an air turbine and which iscompletely removable without carbon deposit during conventionalheat-cleaning operations. These coatings are sometimes called formingsizes, and the forming sizes of the present invention include an organiclubricant which may be of any suitable type, preferably a mineral oil atleast the backbone of which is a hydrocarbon. According to theinvention, it has been found that a forming size containing such alubricant can be heat cleaned without leaving carbon deposits providedthe forming size includes an appropriate amount of a generallynoncrosslinked polymer of an olefin and having disubstituted olefiniccarbon. The exact reason. for the complete removal of the mixture duringheat cleaning is not known precisely, but it is believed to involve anunzipping of the polymer at or substantially near the heat cleaningtemperature to provide volatile hydrocarbons. The sudden flash of thepolymer into volatile material sweeps away the partial pressure of themineral oil to displace the mineral oil from the fibers prior tocomplete pyrolysis of the mineral oil. The unzipping of the polymer willalso provide free :radicals which may induce break down and free radicalformation of the mineral oil. The mineral oil and polymer will notusually be soluble in each other at room temperature, but may at highertemperature, and the polymer will usually be a :solid having good filmforming properties. In order that the above mixture can be convenientlyapplied to the fibers at forming, they preferably are dissolved in amutual solvent which will largely flash away after the size is appliedto the fibers to leave a lubricous coating on the surface of the fibers.The forming size may also include other materials such as cationiclubricants which are attracted to the surface of the glass, and mayfurther include thixotropic gel producing agents which convert the sizeto a gel which can be applied to the fibers under shear conditionswherein the size is a solution and immediately following which it istransformed to a gel.

The lubricating oils which are used can be vegetable oils, butpreferably are high boiling mineral oils which are predominatelyhydrocarbons such as naphthenes. A particularly desirable mineral oil isa retfined petroleum base white oil.

The polymer having disubstituted olefinic carbon can be of any suitabletype, as for example: an acrylic ester polymer, a poly methylstyrene, apolyisobutylene, etc. The radicals attached to the disubstitutedolefinic carbon may include lower alkyl radicals, phenol radicals,halogens, hydroxyl groups, acetoxy groups, amine groups, etc. Thepolymeric film former need not be formed entirely of the disubstitutedolefinic carbon containing material, but may be a copolymer containingsuch material, since the free radicals generated during the unzipping"produce lower polymers such as the dimers and trimers which are volatileat the heat cleaning temperatures.

The solvents which are used can be of any suitable type, and need not bemutual solvents where the polymer to be applied is an emulsion ordispersion. Where acrylic ester polymers are used, Cellosolve acetate isa particularly good mutual solvent of both the acrylic ester polymer andthe mineral oil. The lubricant to polymer ratio should. preferably beless than 1. Sizes of the invention to be applied to the fibers as asolution preferably contain: from approximately I to approximately 25percent by weight of a high boiling lubricant preferably a mineral oilhaving a hydrocarbon backbone, from approximately 5 to approximately 30percent by weight of a polymer of an olefin having disubstitutedolefinic carbon, and up to approximately, 22.5, percentof amptualsolvent and usually ap- BEST AVAILABLE 3 DESCRIPTION OF THEPREFERRED EMBODIMENTS A preferred binder of the present inventionconsists essentially of a highly refined petroleum white oil which is ahydrocarbon composed principally of naphthenes, and an acrylic esterpolymer formed from at least some polymer containing disubstitutedolefinic carbon.

EXAMPLE 1 A liquid binder is made from the following ingredients inpercent by weight:

The binder is prepared by dissolving the cationic lubricant inapproximately one tenth of the Cellosolve acetate to form a premix. Theacrylic ester polymer is thinned with approximately one half of theCellosolve acetate in a Waring blender following which the cationiclubricant premix and the white oil are added, thoroughly mixed, and thendiluted with the remainder of the Cellosolve acetate.

The binder prepared as above described is applied to a sliver formed asdescribed in the Marzocchi-Rammel US. Pat. No. 3,033,719. The binder issprayed onto the filaments before they are collected on the collectingdrum. The coating on the silver comprises approximately 2.0 percent ofthe total weight and is essentially solvent free.

A sliver coated as above described and weighing 0.10 pounds per thousandfeet, was woven into a fabric using 54 pick per inch and 56 fill perinch. This fabric was heat cleaned in an oven at 900 F. No traces ofcarbon remained.

' Cellosolve acetate This material is prepared by adding the cationiclubricant to approximately one tenth of the Cellosolve acetate andheating until dissolved to form a premix. Thereafter the polymer,

white oil and remaining portion of the Cellosolve acetate are added to aWaring Blender and thoroughly mixed, following which the cationiclubricant premix is added. Thereafter the thixotropic gelling agent isadded and the total ingredients blended at a temperature of l 15 F. toproduce a size which is thixotropic at room temperature.

I The above prepared thixotropic gel is applied to the sliver producedas described in the Marzocchi-Rammel US. Pat. No. 3,033,7l9 using theroll applicator described in application Ser. No. 573,348 filed Aug. I6,1966 now US. Pat. No. 3,498,262, and assigned to the assignee of thepresent invention. The roll applicator is positioned to contact thefibers im- A i mediatelybefore -bing pulled -into' the air turbine. Thesliver I prepared with this thixdtropi'c gel" material when *wdiinihto afabric and heat cleaned as above described in Example I has nodetectable carbon deposit.

The ability of materials to be removed from glass fibers by heatcleaning without leaving a carbon deposit can be determined by mixingthe material with fine crushed glass, placing the mixture in depressionsin a porcelain tray, and placing the tray in an oven having an airatmosphere at 900 F.,Table l is a v list of various materials subjectedto this burn-off test, and opposite the materials is a numeraldesignation of the degree of burn-off of the material underconsideration. In this table, 0 indicates a complete removal, numeral 1indicates a perceptible trace, numeral 2 is the maximum allowableamount, and 3, 4 and 5 are gradually increasing heavy amounts ofremaining carbon. The mixture used in these tests in every instancecomprised 2 parts of the fine crushed glass and 0.5 parts by weight ofthe organic mixture.

TABLE I Organic Materials Burn-off rating results I part acrylic esterpolymer (50:50 methyl I methacrylate-ethyl acrylate), l part whitemineral oil, I part Cellosolve acetate I part acrylic ester polymer(50:50 methyl 1 methacrylate-ethyl acrylate), l part white mineral oil,I part toluol 1 part methyl methacrylate, l part white 3 mineral oil, Ipart Cellosolve acetate 1 part poly methylstyrene, l part white Imineral oil, 1 part Cellosolve acetate l part poly isobutylene, l partwhite I mineral oil, 1 part Cellosolve acetate l part acrylic esterpolymer given above, I l part l part 've 1 part acrylic ester polymergiven above, I l

1 part soya oil, I part Cellosolve acetate 1 pan acrylic ester polymer,l part white I mineral oil, I part Cellosolve acetate, one-halfoctadecyl amine acetate l part poly ethyl acetate, 1 part white 3mineral oil, 1 part Cellosolve acetate l part acrylic ester polymer, lpart SAE-IO 1 motor oil, I part Cellosolve acetate FFE In general,materials burn off more poorly in the tray test than they do as acoating on glass fibers. This is probably true because the materials onthe try are raised to elevated tem peratures considerably more slowlythan are coatings on the fibers of a woven fabric; so that thedecomposition of the polymer on the tray is less gradual and thevolatile products of decomposition do not sweep away the partialpressure of the oil as efiectively. It will also be apparent thatcationic lubricants, nonionic lubricants, and other low melting organicmaterials that do not contain metal ions can be present in the sizematerial without changing the synergistic affect of the disubstitutedolefinic carbon polymers on the high boiling organic materials.

The polymer of an olefin having disubstituted olefinic carbon may beused in an amount ranging from an amount approximately equal to the highboiling organic lubricant to an amount approximately 10 times theorganic lubricant. The weight of the polymer and lubricant in thecoating on the fibers will usually comprise from approximately 1 toapproximately 5 percent by weight of the coated fibers in order toadequately lubricate and protect the fibers. in order that good bum-offis had, the fibers should be dry at the time of burn-off. Preferably,the coated fibers should have less than 0.1 percent of moisture beforebum-off is attempted.

As previously indicated, the sizing materials of the present inventionhave particular advantages for the protection of glass fibers as theypass through sliver producing machinery. The size thereafter alsoprovides improved protection for the fibers during the yarn makingoperation wherein several slivers, usually three or more, are uncoiledfrom packages,

6 that the yarn can thereafter be quilled, beamed and woven, withoutfurther application of a lubricant or protective coating. As previouslyindicated, the size provides greatly improved burnoff of the wovenfabric and/or the sliver, yarn or other multiple filament form of thecoated glass fibers.

While the invention has been described in considerable detail, 1 do notwish to be limited to the particular embodiments shown and described;and it is my intention hereby to cover all adaptations, modificationsand arrangements thereof which come within the practice of those skilledin the art and which are covered by the following claims.

1 claim:

1. Glass fibers having a coating thereon consisting essentially of: .1part by weight of a high boiling organic lubricant material; and fromapproximately 1 part to approximately parts by weight of a methacrylateester polymer or copolymer, said coating comprising from approximately 1to approximately 5 percent of the weight of the coated fibers.

2. The glass fibers of claim 1 wherein the high boiling material is amineral oil having a hydrocarbon backbone.

3 The glass fibers of claim 1 wherein the lubricant and polymer aredeposited from a mutual solvent.

4. The glass fibers of claim 1 wherein the solvent is monoalkyl ethersof ethylene glycol acetate, or dialkyl ethers of ethylene glycolacetate, or mixtures thereof.

5. The glass fibers of claim 1 including a gelling agent in sufficientquantity to form a gel at room temperature.

6. The glass fibers of claim 1 wherein the coating consists essentiallyof a mineral oil having a hydrocarbon backbone and a methacrylate esterpolymer or copolymer in approximately a 19 to parts by weight ratio.

7. The glass fibers of claim 1 comprising the following solids inpercent by weight: approximately 19 percent of a mineral oil having ahydrocarbon backbone; approximately 70 percent of a methacrylate esterpolymer or copolymer; approximately 0.5 percent of a cationic lubricant;and approximately 10 percent of a gelling agent.

8. Sliver formed of the coated glass fibers of claim 1.

9. Yarn formed of the sliver of claim 8.

l0. Woven fabric formed of the yarn of claim 9.

1 l. The process of producing heat cleanable sliver comprising:attenuating molten streams of glass into nascent fibers, coating saidnascent fibers with a material consisting essentially of: fromapproximately 1 to approximately 25 percent by weight of a mineral oilhaving a hydrocarbon backbone, from approximately 5 percent toapproximately 30 percent of a methacrylate ester polymer or copolymer,and up to approximately 92.5 percent by weight of monoalkyl ethers ofethylene glycol acetate, or dialkyl ethers of ethylene glycol acetate,or mixtures thereof.

12. The process of claim 11 followed by twisting several sliverstogether to form a yarn.

2. The glass fibers of claim 1 wherein the high boiling material is amineral oil having a hydrocarbon backbone.
 3. The glass fibers of claim1 wherein the lubricant and polymer are deposited from a mutual solvent.4. The glass fibers of claim 1 wherein the solvent is monoalkyl ethersof ethylene glycol acetate, or dialkyl ethers of ethylene glycolacetate, or mixtures thereof.
 5. The glass fibers of claim 1 including agelling agent in sufficient quantity to form a gel at room temperature.6. The glass fibers of claim 1 wherein the coating consists essentiallyof a mineral oil having a hydrocarbon backbone and a methacrylate esterpolymer or copolymer in approximately a 19 to 70 parts by weight ratio.7. The glass fibers of claim 1 comprising the following solids inpercent by weight: approximately 19 percent of a mineral oil having ahydrocarbon backbone; approximately 70 percent of a methacrylate esterpolymer or copolymer; approximately 0.5 percent of a cationic lubricant;and approximately 10 percent of a gelling agent.
 8. Sliver formed of thecoated glass fibers of claim
 1. 9. Yarn formed of the sliver of claim 8.10. Woven fabric formed of the yarn of claim
 9. 11. The process ofproducing heat cleanable sliver comprising: attenuating molten streamsof glass into nascent fibers, coating said nascent fibers with amaterial consisting essentially of: from approximately 1 toapproximately 25 percent by weight of a mineral oil having a hydrocarbonbackbone, from approximately 5 percent to approximately 30 percent of amethacrylate ester polymer or copolymer, and up to approximately 92.5percent by weight of monoalkyl ethers of ethylene glycol acetate, ordialkyl ethers of ethylene glycol acetate, or mixtures thereof.
 12. Theprocess of claIm 11 followed by twisting several slivers together toform a yarn.